Syringes have long been used to inject medications and other fluids into the bloodstream of patients. Syringes are also used to aspirate or withdraw various fluids from patients. These fluids include blood, for example.
When a syringe is used, the contact of the syringe needle with the patient can lead to contamination of the syringe, including the needle, with various contagious micro-organisms. The contaminated syringe and needle then pose a risk to anyone handling the syringe if the person accidentally pricks or contacts themself or someone else with the contaminated needle.
The danger of infection from contaminated needles and syringes has become of increased concern with the discovery of HIV (human immunodeficiency virus) which causes AIDS (Acquired Immune Deficiency Syndrome). The danger also exists for other infectious diseases and infections, such as hepatitis, streptococcal sepsis, tetanus, tuberculosis, Rocky Mountain Spotted Fever, and malaria.
The problem is especially relevant in the health care industry. Each year, 7% of hospital employees are involved in needle stick injuries, of which 60% are nurses. It is estimated that 57% of accidental needle sticks occur while attempting to recap the needle of a syringe or in disposal of the syringe. It is also estimated that in excess of $28.3 million is spent annually in the United States for the diagnosis and initial treatment of needle sticks.
Various strategies to deal with this problem have been attempted. One approach involves the use of some sort of cap to cover the syringe needle after use, to prevent contact with the needle. This cap can be as simple as the original plastic cap which is used to cover the needle prior to use. However, the motion required to replace the original needle cap allows for error resulting in needle contact. This is due to the relatively small diameter of the cap and the required movement of a hand toward the contaminated needle during cap replacement.
Other approaches provide for additional means for covering the needle, in the form of shields. Examples of shields are provided in U.S. Pat. Nos. 4,666,435; 4,871,355; 4,923,447; 4,998,920; and 5,098,403.
The goal of a shield is to provide a means for preventing pricks and contact with contaminated needles, without interfering with the normal usage of a syringe. The shield must also be easily manufactured in conjunction with a syringe or easily assembled onto an existing syringe if manufactured separately. Ways to make a shield in a cost-effective manner are also important.
Although various types of shields have been proposed, the severity of the AIDS epidemic and other infectious diseases/infections provides a continuous need for an apparatus for shielding a syringe needle which meets these requirements.